The All-22: Keenan Allen's remarkable rookie season in San Diego

The San Diego Chargers may not make the playoffs (they have to win out and get some help) and Keenan Allen may not win Offensive Rookie of the Year (Eddie Lacy, anyone?), but together that pairing has a bright future.

Because of the knee injury he suffered in 2012 at Cal -- and some slow 40 times that occurred as he was still rehabbing -- Allen slipped into the third round of the 2013 draft. There, the Chargers absolutely stole him. He's since become Philip Rivers' go-to weapon in the passing game, with 63 receptions, 931 yards and seven touchdowns.

The main reason for his success: He entered the NFL with a polished game, leaving college a developed route-runner and a receiver capable of positioning his body to beat defenders. The Chargers have taken advantage of that development in many ways this season.

To fully appreciate what Allen has done this season, I circled back to watch all 63 of his catches. Here's what I saw ...

Let's start here, with a simple example of why Allen has been so good in his first NFL season:

From left to right, that's Allen lined up ... well, left to right. The Chargers do not hesitate to move Allen around the field, and he's set up in all of the X, Y and Z spots this year. Quite frequently, as on that first shot, he'll have one side of the field to himself. But he's also scored multiple touchdowns out of the slot and in overloaded formations.

Plenty of receivers shift around over the course of the game -- Calvin Johnson, arguably the best wideout in football, opened Monday night in the slot versus Baltimore, for example. But not every receiver is capable of doing so, nor does every receiver have the acumen to produce from different areas of the field. Allen, however, showed this potential back at Cal, where former head coach Jeff Tedford allowed his talented receiver to explore the field.

So, Allen was ahead of the game when he landed in the NFL, with experience running varied routes to all areas of the field.

Below, you'll find a rough chart of where Allen's 63 receptions have occurred on the field:

Anything stand out?

How about this: There's not one dot beyond about 25 yards downfield. Rarely have the Chargers asked Allen to stretch the field vertically; when they do, it's often in the red zone, as evidenced by his TD on a corner route versus Denver last week.

I'd also like to point out the sheer volume of yellow dots inside the numbers and within a 10-yard window. Allen makes a ton of his catches there because A.) San Diego tries hard to get the ball in his hands early, so he can create; and B.) he's excellent on slants and in-routes, able to get defenders on his back hip so Rivers has somewhere to hit him.

On point A ... by my count, approximately 15 percent of Allen's catches this season have come on underneath crossing routes. There's nothing fancy or groundbreaking about these routes, but it serves the purpose of clearing some space, thus allowing Allen to create with the football in his hands.

One example below, from San Diego's game with Indianapolis. The Chargers set Rivers in the shotgun, with a back and a trips formation to his right. Allen lined up alone to Rivers' left (yellow box, below), then ran a shallow route about three yards downfield.

Essentially, this became a screen for Allen. The running back fired out to pick up a linebacker, while the two WRs and tight end Antonio Gates (the three in that trips setting) released between the hash marks and the sideline. Allen caught the ball coming across the middle, then followed those blockers for a solid gain.

But he usually doesn't need any extra help generating open space. Case in point, another of the Chargers' favorite Rivers-to-Allen routes: the slant.

It's easy to take for granted that NFL receivers will be able to succeed in that route when facing one-on-one coverage. Allen does it consistently. That play above puts on display both Allen's ability to run crisp, compact routes and his skill at getting around to the football with his hands and body.

Those traits are all put to work when Allen executes deep in routes, too. (Thanks to CBS' Dan Fouts for providing the telestrator detail here ...)

A route like that one requires a receiver to get a good release off the line, then to break off with a sharp enough cut to prevent the defender from coming over the top. Allen excels at it. I counted no fewer than 14 receptions this season off a similar route, plus a couple more coming when Allen faked the cut in and broke back to the sideline instead.

On this play pictured, Washington's David Amerson was able to run stride for stride with him, but as soon as Allen planted his foot, he had clearance.

Rivers -- and San Diego's scheme -- deserves a lot of credit for putting Allen in position to produce this season. That said, we've seen explosive rookie receivers such as Cordarrelle Patterson and Tavon Austin slump at times because they require more creative methods for getting them the football.

Allen is an advanced specimen at receiver, especially in terms of his development as a route-runner. He may never be a player who's going to burn defenses long over and over again, like a Torrey Smith or Josh Gordon. He'll also rarely have games where the opposition can keep him totally contained.